The Didact

The Didact was a high-ranking figure in Forerunner society and the supreme commander of the Forerunner military. He was part of the Warrior-Servant caste of Forerunner, and had reached the highest rank achieveable in this domain. He studied the Percursors, an ancient race that was far more advanced than the forerunners, and eventually was only second to the Librarian herself in the knowlege of the mysterious civilization. He was sent into self-imposed exile (or cryptum) on Earth, or Erde-Tyrene, as it was known at the time, for the reason that he opposed the firing of the HALO Arrays.